Pregnancy and obesity: Know the risks

Being obese during pregnancy can have a major impact on your health and your baby's health. Find out about the possible complications, recommendations for weight gain and what you can do to promote a healthy pregnancy.

What's considered obese?

Obesity is defined as having an excessive amount of body fat. A formula based on height and weight — called the body mass index (BMI) — is often used to determine if a person is obese.

BMI

Weight status

Below 18.5

Underweight

18.5-24.9

Normal

25-29.9

Overweight

30 and higher

Obese

40 and higher

Extreme obesity

Could obesity affect my ability to get pregnant?

Being obese can harm your fertility by inhibiting normal ovulation. Obesity can also affect the outcome of in vitro fertilization (IVF). As a woman's BMI increases, so does the risk of unsuccessful IVF.

How might obesity affect my pregnancy?

Being obese during pregnancy increases the risk of various pregnancy complications, including:

Gestational diabetes. Women who are obese are more likely to have diabetes that develops during pregnancy (gestational diabetes) than are women who have a normal weight.

Preeclampsia. Women who are obese are at increased risk of developing a pregnancy complication characterized by high blood pressure and signs of damage to another organ system, often the kidneys (preeclampsia).

Infection. Women who are obese during pregnancy are at increased risk of urinary tract infections. Obesity also increases the risk of postpartum infection, whether the baby is delivered vaginally or by C-section.

Overdue pregnancy. Obesity increases the risk that pregnancy will continue beyond the expected due date.

Labor problems. Labor induction is more common in women who are obese. Obesity can also interfere with the use of certain types of pain medication, such as an epidural block.

C-section. Obesity during pregnancy increases the likelihood of elective and emergency C-sections. Obesity also increases the risk of C-section complications, such as wound infections. Women who are obese are also less likely to have a successful vaginal delivery after a C-section (VBAC).

Committee to Reexamine IOM Pregnancy Weight Guidelines, Food and Nutrition Board, and Board on Children, Youth and Families. Weight gain during pregnancy: Reexamining the guidelines. Institute of Medicine and National Research Council. http://www.nap.edu. Accessed March 10, 2015.

Staying healthy and safe. U.S. Department of Health and Human Services Office on Women's Health. http://womenshealth.gov/pregnancy/you-are-pregnant/staying-healthy-safe.html. Accessed March 10, 2015.

Loret de Mola JR. Obesity and its relationship to infertility in men and women. Obstetrics and Gynecology Clinics of North America. 2009;36:336.

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